Since, I think, installing Yosemite, I’ve been plagued by dialogs asking me whether to allow an application to accept incoming connections. It happens when I launch Messages, run unit tests in Xcode the first time after launch, and certain times when I run xcodebuild.

In the Security & Privacy ‣ Firewall pane of System Preferences, I have the firewall on, but all of these executables are set to Allow incoming connections. Their code signatures check out, so the system should remember what I’ve allowed and not keep prompting. This used to work.

I've yet to try the Kessler solution I suggested above because, to add insult to the injury, I don't have this issue on my Air, only on my desktop. Both run on 10.10, but I had the problem on the Mac Pro also in previous releases, starting 10.8.

This limited to specific apps or is it is a general issue? I had this happen with iTunes a few years ago. It turned out that something in the app package got modified and the signature was no longer valid. (I think - it _was_ a few years back). With the invalid sig, the system would ask me about incoming connections on each launch.